Manipulator for an instrument for minimally invasive surgery and such an instrument

ABSTRACT

A manipulator for an instrument for minimally invasive surgery, provided with a first moveable carriage, on which first carriage the instrument can be mounted, wherein the first carriage is positioned on a first arm of a parallelogram construction to provide the instrument with a virtual pivoting point in the plane in which during use the instrument intersects the body of a patient, wherein the proximal end of the manipulator is provided with a handle for operating the instrument with the handle being placed on, or forming part of a second arm of the parallelogram construction opposite the first arm, such that a body axis of the handle always extends parallel to the instrument.

The invention relates to a manipulator for an instrument for minimallyinvasive surgery, provided with a first moveable carriage, on whichfirst carriage the instrument can be mounted, wherein the first carriageis positioned on a first arm of a parallelogram construction to providethe instrument with a virtual pivoting point in the plane inwhich—during use—the instrument intersects the body of a patient. Theinvention also relates to an instrument to be used with such amanipulator, comprising a tube provided at its first end with amouthpiece and wherein control means for the mouthpiece pass through thetube.

A manipulator of the kind mentioned in the preamble is known from theinternational patent application no. WO 00/30557.

In the known manipulator the instrument is motor-driven. Such amanipulator is costly, requires the necessary training for use and hasthe additional disadvantage that the surgeon using the manipulator feelsno force feedback from the resistance the instrument encounters during asurgical operation. In addition, the surgeon often experiences a delaybetween the movement of his hand and that of the instrument.

It is the object of the invention to provide such a manipulator that issimple, less costly, smaller, lighter and providing the surgeon usingthe manipulator with an undelayed force feedback, as well as allowingthe surgeon to assume a natural posture when operating that matches thepositioning of the instrument at that moment.

To this end the manipulator according to the invention is characterisedin that the proximal end of the manipulator is provided with a handlefor operating the instrument, with the handle being placed on, orforming part of a second arm of the parallelogram construction oppositethe first arm, such that a body axis of the handle always extendsparallel to the instrument.

The manipulator according to the invention has the advantage that thereare no motor drives, and with respect to positioning there is aone-to-one coupling between the handle of the manipulator and theinstrument being operated with the aid of the manipulator. This is aninestimable advantage to the surgeon using the manipulator, whichespecially aids the operational ease and the applicability of themanipulator for surgical uses.

To this end it is further advantageous for the handle to be positionedon a moveable second carriage coupled with the first carriage such thatwhen moving the second carriage, the first carriage carries out acorresponding movement in the longitudinal direction of the instrument.

It is further desirable for the instrument to be detachable from thefirst carriage. This affords the possibility of easily adapting theinstrument to the actions to be carried out during the surgicaloperation, while the necessary sterilisation activities can be limitedto this instrument.

In this connection, the manipulator according to the invention may besuitably embodied such that a first carriage is provided with couplersdesigned to co-operate with control organs of the instruments, whichcouplers are coupled with the handle via interpositioned pull wires. Theapplication of pull wires is favourable both with respect to limitingthe weight of the manipulator that has to be displaced during use, andalso to limiting friction and to avoiding possible play.

In a further aspect of the invention the manipulator is characterised inthat the instrument is coupled with the handle in order to be able toconduct in unison (not delayed) a rotation about the respective bodyaxes.

As already mentioned above, the invention is also embodied in aninstrument that is equipped for use with a manipulator as describedabove. According to the invention, this instrument is characterised inthat at a second end of the tube opposite to the first end comprisingthe mouthpiece, control organs are provided that are coupled with thecontrol means for the mouthpiece that are passing through the tube.

Advantageously this instrument is embodied such that the control organsare flanges mounted on pull tubes passing through the tube andconstituting part of the control means. The use of flanges affords thepossibility of a readily detachable coupling between the control organsof the instrument and the couplers of the manipulator, which in turn areoperated by means of the handle. The advantage of using pull tubes isthat they are also suitable for exerting a pushing force.

The instrument according to the invention is preferably characterised inthat the mouthpiece is a jaw-like gripping organ comprising twocooperating jaw portions, wherein each jaw portion is coupled with oneof the pull tubes.

An optimisation of the adjustment potential of the instrument accordingto the invention is possible if the gripping organ has two orthogonaldirections of rotation, both of which are at right angles in relation tothe longitudinal axis of the instrument.

It is further preferred for the jaw portions to be spring-activated soas to force the jaw portions apart to open the gripping organ. By thusproviding the-necessary opening force for opening the jaw portions ofthe gripping organ locally, by means of a spring, the diameter of theinstrument can be kept to a limit; after all, in order to open the jawportions there is no need for a separate control organ that would haveto pass through the tube of the instrument.

Mounting the manipulator on the operating table allows the manipulatorto be used as instrument holder or clamp. The freedom of movement of themanipulator may be designed to include the possibility of locking bymeans of (for example) break shoes operated by means of (for example) afoot pedal. In this way it is possible to use the manipulator hands-freeso as to simultaneously allow other tasks to be performed.

Below the invention will be elucidated in more detail with reference tothe drawing of a non-limiting preferred exemplary embodiment of themanipulator and the instrument according to the invention.

The drawing shows in:

FIGS. 1 and 2 the manipulator with the instrument according to theinvention;

FIG. 3 the whole instrument according to the invention and a detailedview of the mouthpiece;

FIG. 4 the whole instrument according to the invention, as well as adetailed view of a first end and a detailed view of a second end;

FIG. 5 the instrument according to the invention as shown in FIG. 4,with the mouthpiece being slightly rotated; and

FIG. 6 the instrument according to the invention in mounted positiontogether with a portion of the manipulator.

Identical reference numbers in the figures refer to similar parts.

Referring to FIG. 1, this figure shows an instrument 1 for laparoscopicsurgery, which may be partly within the body of a patient and enjoyingsix degrees of freedom indicated at the mouthpiece of the instrument,being the three translations x, y and z and the three rotations α, β andγ. All these movements are controlled by operating a handle 2, whichenjoys the same degrees of freedom, and which during operation of thehandle relays the same one-to-one to the mouthpiece of the instrument.In addition, there is a seventh degree of freedom formed by the open andclose movement of the handle 2 and the open and close movement of thejaws of the mouthpiece coupled thereto, as will be explained below.

At the place where via an incision the instrument 1 is inserted in apatient's body, the instrument 1 has, according to the invention, aninvariant point 3. When operating the instrument 1 by means of thehandle 2, this invariant point 3 forms a virtually fixed point ofrotation for the instrument 1.

With reference to FIG. 2, it is shown that the basis of the manipulatoris formed by a main axis 4 that is capable of carrying out a rotation ωdue to said main axis 4 being accommodated in a bearings 5 coupled withthe solid world. This solid world is preferably formed by an operatingtable. With this main axis 4 a known so-called parallelogram mechanismis connected of which plates 6 and 7 and a tube 8 are elements. By meansof this parallelogram mechanism a rotation δ of the handle 2 about axis9 a is translated into a correspondihg rotation δ about the axes 9 b and9 c and axis 10, which is located outside the parallelogram mechanismand (in its extended direction) intersects the main rotation axis 4.This point of intersection coincides with the above-mentioned incisionin the patient's body, which coincides with the above referred-to fixedvirtual point of rotation. The fore-going thus explains that theinstrument 1 is capable of carrying out two rotations δ and ω about thefixed virtual point of rotation 3.

For the control of other movements the instrument is capable of, thereare, for example, pull-wires leading from the handle 2 through themanipulator to the instrument. The movement of handle 2 and instrument 1in the longitudinal direction z of the instrument occurs, for example,due to the handle and instrument being situated on carriages 12 and 13that are moveable along guidings.

The working of the instrument according to the invention will now befurther elucidated with reference to the FIGS. 3-6.

In FIG. 3 is shown that the mouthpiece of the instrument 1 is embodiedas jaw-like gripping organ comprising two cooperating jaw portions 15,16, each of which is able to rotate individually about axis 17. Therotations β and ν of the jaw portions 15 and 16 are each controlledseparately by means of cables that are connected to pull tubes 23 and 22extending in the instrument 1 (see also FIG. 4). By contracting the pulltubes 23 and 22 simultaneously the jaw portions 15 and 16 are caused toclose. The jaw portions are also spring-activated by means of a spring18 (see FIG. 3), which produces an opening force for the jaw portions15, 16.

FIG. 5 shows that when only pull tube 22 is contracted and pull tube 23is slack, both jaw portions 15, 16 will rotate about axis 17 indirection ν. The instrument 1 is further embodied such that the jawportions 15, 16 are also able to rotate about an axis 19. To this end apull-push tube is used which, when pushing in the direction of the jawportions 15, 16, will rotate the same in the direction of rotationindicated by α.

FIGS. 4 and 5 further show that at the end furthest from the jawportions 15, 16, the pull tubes 22 and 23 are provided with flanges 25and 26. At the respective end, pull-push rod 24 is provided with a ball27. The function of the flanges 25 and 26 and the ball 27 will becomeclear in the explanation below referring to FIG. 6.

FIG. 6 shows the instrument 1 mounted on the carriage 13 and moveablealong a guiding. The flanges 25 and 26 that are coupled via theabove-mentioned pull rods with the jaw portions 15, 16 of themouthpiece, are operated by means of levers 28 and 29, which are part ofthe manipulator. The pull-push rod 24 is operated by a disc 30 connectedto the ball 27. This latter connection is designed such that thanks tothe shape of the ball 27, the instrument 1 is rotatable about itslongitudinal axis. By controlling the levers 28 and 29 and the disc 30,the rotations α, β and ν of the jaw portions 15, 16 are controlled.Incidentally, the ball 27 and the disc 30 cooperating therewith, as alsoother construction parts, may be replaced by another constructionworking in a similar manner, for example, by a rotatable flangecontrolled by means of a moveable carriage. Rotation γ of the instrument1 is effected by operating the disc 31.

The coupling of the levers 28 and 29 and disc 30 with the handle 2, isin the present exemplary embodiment effected by means of pull wires.However, within the scope of the invention it is also possible toprovide other types of couplings between the handle 2 and the operatingmembers of the instrument 1. Such couplings may be bowden cables,hydraulics, chains, bands or the like. All this lies within the scope ofthe person skilled in the art and requires no further explanation.

1. A manipulator for an instrument for minimally invasive surgery,provided with a first moveable carriage, on which first carriage theinstrument can be mounted, wherein the first carriage is positioned on afirst arm of a parallelogram construction to provide the instrument witha virtual pivoting point in the plane in which during use the instrumentintersects the body of a patient, wherein proximal end of themanipulator is provided with a handle for operating the instrument, withthe handle being placed on, or forming part of a second arm of theparallelogram construction opposite the first arm, such that a body axisof the handle always extends parallel to the instrument.
 2. Amanipulator according to claim 1, wherein the handle is positioned on amoveable second carriage coupled with the first carriage such that whenmoving the second carriage, the first carriage carries out acorresponding movement in a longitudinal direction of the instrument. 3.A manipulator according to claim 1, wherein the instrument is detachablefrom the first carriage.
 4. A manipulator according to claim 1, whereinthe first carriage is provided with couplers designed to co-operate withcontrol organs of the instrument, which couplers are coupled with thehandle via interpositioned pull wires.
 5. A manipulator according toclaim 1, wherein the instrument is coupled with the handle in order tobe able to conduct in unison a rotation about the respective body axes.6. A manipulator according to claim 1, additionally comprisingadjustable locking facilities for fixing the manipulator in one orseveral directions.
 7. An instrument for minimally invasive surgerysuitable for use with a manipulator in accordance with claim 1,comprising a tube provided at its first end with a mouthpiece whereincontrol means for the mouthpiece pass through the tube, and wherein at asecond end of the tube opposite to the first end comprising themouthpiece control organs are provided that are coupled with the controlmeans for the mouthpiece that are passing through the tube.
 8. Aninstrument according to claim 7, wherein the control organs are flangesmounted on pull tubes passing through the tube and constituting a partof the control means.
 9. An instrument according to claim 7, wherein themouthpiece is a jaw-like gripping organ comprising two cooperating jawportions, wherein each jaw portion is coupled with one of the pulltubes.
 10. An instrument according to claim 9, wherein the grippingorgan has two orthogonal directions of rotation, both of which are atright angles in relation to the longitudinal axis of the instrument. 11.An instrument according to claim 9, wherein the jaw portions arespring-activated so as to force the jaw portions apart to open thegripping organ.